diff --git a/src/core/mac/mac.cpp b/src/core/mac/mac.cpp
index dd8d3540e..74ed3ad53 100644
--- a/src/core/mac/mac.cpp
+++ b/src/core/mac/mac.cpp
@@ -381,6 +381,7 @@ void Mac::SendBeaconRequest(Frame &aFrame)
 
 void Mac::SendBeacon(Frame &aFrame)
 {
+    uint8_t numUnsecurePorts;
     uint16_t fcf;
 
     // initialize MAC header
@@ -389,6 +390,18 @@ void Mac::SendBeacon(Frame &aFrame)
     aFrame.SetSrcPanId(mPanId);
     aFrame.SetSrcAddr(mExtAddress);
 
+    // set the Joining Permitted flag
+    mNetif.GetIp6Filter().GetUnsecurePorts(numUnsecurePorts);
+
+    if (numUnsecurePorts)
+    {
+        mBeacon.SetJoiningPermitted();
+    }
+    else
+    {
+        mBeacon.ClearJoiningPermitted();
+    }
+
     // write payload
     memcpy(aFrame.GetPayload(), &mBeacon, sizeof(mBeacon));
     aFrame.SetPayloadLength(sizeof(mBeacon));